1. Field of the Invention
This invention relates, in general, to voltage regulators and, more specifically, to voltage regulators having current limiting circuitry.
2. Description of the Prior Art
Voltage regulators are commonly used to provide a constant output voltage to power various electronic devices. Typically, such voltage regulators operate on the technique of pulse width modulation wherein the conduction time of switch control elements is varied in proportion to the magnitude of the output voltage of the regulator so as to control the amount of energy transferred to an output transformer and thereby maintain the magnitude of the output voltage at a constant level.
Such voltage regulators are also provided with current limiting capabilities which protect the switch elements and the electronic devices from overcurrent conditions. As shown in U.S. Pat. No. 3,978,393, which is assigned to the assignee of the present application, current limiting capability for a voltage regulator is provided by a differential input comparator which detects an overcurrent condition and generates a control signal which terminates the supply of power to the switching elements of the voltage regulator. Although such a current limiting arrangement is effective to protect the voltage regulator and the electronic utilization devices, it would be more desirable to provide a voltage regulator having current limiting capabilities wherein the output current of the voltage regulator is linearly reduced until the overcurrent condition is removed.